The present invention relates to a conveying system for materials to be processed by a press and, more particularly, to a system which is installed between presses to convey partly finished products which have been worked by one press to another press.
There have been known two types of such conveying systems for continuously conveying press materials, i.e. the transfer press type and the transfer press line type. The former is characterized in that plural metal molds are installed in one press unit, and a pair of feed bars parallel to the metal molds and fingers mounted on the feed bars are provided to sequentially convey materials to the metal molds for continuous working. The transfer press line, on the other hand, comprises plural presses, and feed bars which are of a length identical to that of a press and have fingers similarly to the former type, the feed bars being driven to sequentially feed materials to press metal molds.
The transfer press type of system is advantageous in that the system can be made compact as 8 to 10 metal molds are arranged in one press without leaving any space therebetween. However, as all the upper molds are attached on a slide (a ram), the press is driven irrespective of the necessary number of work steps and therefore if materials can be processed to form a product in a lesser number of steps than the total of the metal molds, a number of the metal molds are idled, which is uneconomical. If the work requires more working steps than the number of metal molds, on the other hand, a product cannot be completed in the press, presenting inconvenience and disadvantages.
Although a desired number of presses may be installed in the transfer press line type of system, if too many presses are installed, the feed bars become too long to be driven smoothly. In the transfer press line, presses must be arranged in the linear direction and the metal molds of the respective presses must be aligned in height in order to convey materials properly. This can be inconvenient to the operation, since operation of the machines is unnecessary for particular work can be suspended, operation of the feed bars cannot be suspended.